This invention relates to a device intended to prevent the siphon back flow in the hydraulic faucet valves comprising a cartridge which contains flux control members shaped as plane plates of hard material.
When a faucet valve is used to control a flux through a shower or any other delivery member which is connected through a hose, there is the possibility that the delivery member is immersed in a liquid containing basin. If, in such circumstances, the water delivery is interrupted and the supply pipes are evacuated, for example in order to proceed to a repair, within the pipes there may establish a transitory underpressure. As a consequence of such underpressure, if the faucet is open there may take place a siphon back flow, and some liquid contained in the basin is sucked, through the delivery member and the faucet, up to the supply pipe. This leads to a possible pollution of the supply pipe and possibly of the aqueduct too.
In order to prevent such phenomenon, the showers and other delivery members intended to be connected to a faucet through a hose are usually provided with a back flow preventing valve. However the operation of such back flow preventing valves may easily be hindered by foreign bodies or dirt, and for this reason some regulations impose that the installations referred to should be provided with protection means suitable for preventing the establishment of any underpressure downstream of the faucet.
Mounting a special aeration valve, arranged downstream of the faucet, which allows air inlet when an underpressure arises, gives a solution to this problem, but involves undesiderable additional costs. On the contrary it is desirable that such an aeration valve be embodied in the faucet itself. This problem has been already solved with respect to faucets having a ball shutter. Therein the valve may be located within the ball shutter, by giving rise to a very limited increase in cost.
On the contrary, this problem has not been solved as yet with respect to the hydraulic faucet valves provided with a cartridge comprising flux control members shaped as plane plates of hard material. Mounting an aeration valve within a cartridge of this kind raises problems whose solution is somewhat difficult, and moreover involves the need for manufacturing special cartridges which differ from the usual ones in being provided with an aeration valve. This is undesirable, on one hand because of the increase in the number of cartridge types to be manufactured, and on the other hand because the wrong replacement of a usual cartridge to a cartridge provided with aeration valve could easily lead to unintentionally violate the prevention regulations. On the contrary, it is desirable that the aeration valve be embodied in the faucet rather than in the replaceable cartridge, whereas on the other hand it is also desirable that usual cartridges may be mounted in a thus equipped faucet valve.